Process for preparing 2,4,4,4-tetrachlorobutanol

ABSTRACT

Carbon tetrachloride and allyl alcohol are reacted, in the presence of an improved catalyst system comprised of iron powder, iron chloride and a free radical generating azo compound, to obtain 2,4,4,4-tetrachlorobutanol in high yield and purity. The resulting chlorinated alcohol product is of utility in preparing 4,4,4-trichlorobutylene oxide which in turn is a useful intermediate in the preparation of chlorinated polyether polyols employed in making flame-retardant polyurethane foam.

United States Patent Kaiser et al. I

PROCESS FOR PREPARING 2,4,4,4- TETRACHLOROBUTANOL [75] Inventors: DonaldW. Kaiser, Hamden; Craig K. Wood, North Haven, both of Conn.

[73] Assignee: Olin Corporation, New Haven,

' Conn.

[22] Filed: Dec. 21, 1970 [21] Appl. No.: 100,351

[52] US. Cl ..260/633 [51] Int. Cl ..C07c 31/34 [58] Field of Search..260/633, 658 C [56] References I UNITED STATES PATENTS 3,399,2418/1968. Smith ..260/633 3,399,217 8/1968 Zaslowsky 3,309,393

3/1967 Nakagawa et al ..260/658 C FOREIGN PATENTS OR APPLICATIONS1,207,366 12/1965 Germany ..260/633 OTHER PUBLICATIONS Le Coq et al., c.R. Acad. Sc. Pan's, Series C, t264, pp. 12004203, 1967.

- Prima ry Examiner--Howard T. Mars Attorney-F, A. Iskander, Gordon D.Byrkit, Donald F. Clements, Thomas P. ODay and E. Zagarella polyetherpolyols employed in making flame-retardant polyurethane foam.

10 Claims, No Drawings PROCESS FOR PREPARING 2,4,4,4-TETR'ACHLOROBUTANOL This invention relates to an improved process formaking 2,4,4,4-tetrachlorobutanol. More particularly, the inventionrelates to a novel catalyst system for use in the preparation of2,4,4,4-tetrachlorobutanol by the reaction of allyl alcohol with carbontetrachloride.

The compound 2,4,4,4-tetrachlorobutanol, hereinafter referred to asTCBA, is a versatile chemical having a wide range of utility. It reactsin a manner typical of aliphatic alcohols, and its chlorinated naturerenders it highly desirable where high chlorine content is needed, forexample, as a component of pesticides in agricultural applications andthe like. It is also useful as an intermediate in preparing plasticizersfor polyvinyl chloride resins. In addition, TCBA may readily bedehydrohalogenated to give 4,4,4-trichlorobutylene oxide. This lattercompound is a reactive, high chlorine-containing epoxide which is usefulin the preparation of epoxy resins, lubricants, and chlorinatedpolyether polyols employed in the preparation of flame-retardantpolyurethane foam.

U.S. Pat. No. 3,399,217 to Zaslowsky and U.S. Pat. No. 3,399,241 toSmith disclose improved processes for'making TCBA by the reaction ofallyl alcohol with carbon tetrachloride. The Smith patent utilizes areaction catalyst mixture comprised of powdered iron and anhydrousferric chloride, and the catalyst mixture utilized in the Zaslowskypatent comprises, along with the powdered iron and the ferric chloride,calcium carbonate and magnesium sulfate. These patents eliminate priorart drawbacks such as the need to use high reaction temperatures andhigh pressure equipment. However, there is still a need for a catalystsystem for the reaction of allyl alcohol with carbon tetrachloride,which provides higher yields of TCBA.

LeCoq and Levas, in CR. Acad. Sci., Paris, France,

' Ser. C264(l4), 1967 pp. 1200-1203, disclose the use ofazobisisobutyronitrile as a catalyst in the reaction of allyl alcoholwith trichlorobromomethane to obtain good yields oftrichlorobromobutanol. However, when this catalyst is employed in thereaction of allyl alcohol with carbon tetrachloride, a very lowconversion to TCBA is obtained.

Now it has been found, in accordance with this invention, that TCBA, inimproved purity and yield, can be prepared by carrying out the reactionof allyl alcohol with carbon tetrachloride in the presence of acatalytic proportion of a catalyst mixture comprised of iron powder,iron chloride and a free radical generating, azo compound. I

In the reaction of allyl alcohol with carbon tetrachloride, any suitablemolar ratio of allyl alcohol to carbon tetrachloride, ranging from about1:1 to about 1:6, and preferably from about 1:2 to about 1:4, may beemployed.

Any type of iron can be employed as a catalyst component according tothe invention, for example elemental iron, ,wrought iron, stainlesssteel, mixtures thereof, and the like. The iron is employed in powderedform, usually comprising particles all of which pass a 40-mesh screenand preferably all of which pass a 200- mesh screen. Particles having adiameter larger than about 40-mesh may be employed, but the catalyticeffect of these larger particles is reduced inasmuch as their totalsurface area is smaller.

The iron chloride component of the catalyst mixture is preferablyemployed in the anhydrous, sublim'ed powder form. It can be ferrouschloride or ferric chloride, the ferric chloride being preferred.

I Any free radical producing, azo compound may be employed as acomponent in the catalyst mixture of the invention. Illustrative areazobisisobutyronitrile, a'zobisformamide, azodicarbonamide, and thelike. Such compounds upon exposure to heat, lose nitrogen and generatefree radicals. However, it is preferred to use azobisisobutyronitrile.This is a solid material which can be purchased commercially. It can beemployed in its commercially available state.

Typical relative ranges, and preferred relative ranges, of thecomponents of the catalyst mixture employed according to the inventionare provided in Table 1 below.

about 10 60 The catalyst mixture is employed in any catalytic proportionthat is capable of increasing the reaction rate of the allyl alcoholwith the carbon tetrachloride. Thus, based on the total weight of allylalcohol and carbon tetrachloride, a proportion of the catalyst mixtureusually ranging from about 0.5 percent to about 25 percent by weight,and preferably from about 1 percent to about 10 percent may be employed.

Any convenient order of mixing of the reactants and the catalystcomponents may be employed. For example, all of the reactants and thecatalyst components may be added simultaneously to a reactor, and thereactor contents may then be agitated and heated, under reflux, untilthe reaction has attained the desired degreeof completion. However, itis preferred to add the carbon tetrachloride and the individualcatalystmixture components to the reactor first. These are then heated, and theallyl alcohol is added to the agitated mixture incrementally over aperiod of time.

After the reactants and catalytic mixture have been added to thereactor, the agitated reaction mass is heated, preferably under refluxand a nitrogen blanket, at a temperature range of about 95 C., andpreferably about 72-90 C. for the length of time that is necessary toachieve complete reaction of all the allyl alcohol with the carbontetrachloride. Usually the total reaction time ranges from about 4 toabout 15 hours, and preferably from about 5 to about 8 hours, butshorter or longer time periods may be employed if desired.

After the refluxing step has been completed, during which time hydrogenchloride and water are formed in side reactions as minor by-products,and organic phase, containing carbon tetrachloride and TCBA, isseparated, cooled and the solids are removed therefrom by filtration orother convenient solid-liquid separation technique. The solids areformed from unused catalysts or reaction products of the catalyst. Theresulting filter cake is washed with carbon tetrachloride and thendiscarded, the carbon tetrachloride wash being added to the filtrate.The filtrate and wash solution are combined and washed with water toremove any dissolved inorganic salts and.

trapped, unused catalyst. The aqueous phase is then separated from theorganic phase, which, if desired, may be stripped, using a flashevaporator. The purpose of the stripping step is to remove carbontetrachloride and possibly smaller proportions of other volatiles suchas allyl alcohol, and to enable the recovery of the TCBA in highconcentrations.

As indicated above, the product TCBA, by virtue of its high chlorinecontent, can be used as a component of pesticides in agricultural andlike applications. it is also useful, when reacted with a basicdehydrohalogenation agent, in preparing 4,4,4- trichlorobutylene oxidewhich in turn is of utility in preparing epoxy resins, lubricants, andchlorinated polyether polyols tion of flame-retardant poly-urethanefoam. When-used to prepare trichlorobutylene oxide, the crude organicphase of TCBA, prepared as described above, can be which are employed inthe prepara used directly, without stripping off its volatilecomponents.

In a preferred embodiment of the invention, the catalyst mixture alsocomprises a certain proportion of calcium carbonate. Typically this mayrange from about 1 to about 75 percent, and preferably from about 10 toabout 40 percent, by weight based on the total weight of the catalystmixture.

It is also preferred to include in the catalyst mixture varyingproportions of an anti-oxidant. Illustrative antioxidants. are butylatedhydroxyanisole, butylated hydroxytoluene,2,2'-methylene-bis-4-rnethyl-6-tertiarybutylphenol, and the like. Thebutylated hydroxyanisole is particularly preferred. Any effectiveproportion of theanti-oxidant may be employed such as about 0.5 -20percent,'and preferably 1-10 percent, by weight based onthe total weightof the .catalyst mixture. Surprisingly, the inclusion of an antioxidant,which is known to destroy free radicals, has been found to furtherincrease the yield of TCBA product.

By utilizing the catalyst mixture of the invention full conversion ofthe allyl alcohol and an improved yield and purity of the product TCBAcan be obtained. Typically, yields as high as about 80-90 percent areobtained and the purity of the product TCBA exceeds 80 percent. Theseresults are particularly .surprising in view of the fact that but forthe presence of the azo compound, e.g., azobisisobutyronitrile, in thecatalyst mixture, such yields would be unobtainable. Yet if thisazo-compound is used in the absence of the iron and the iron chloride, avery low conversion to TCBA results.

The following examples are provided to illustrate the invention. Inthese examples, all parts and percentages are by weight unless otherwisespecified.

EXAMPLE l stirred mixture was heated, by means of an electricalheatingmantle surrounding the flask, to about 76-79 C. to obtain reflux. Then58 grams (1 mole) of allyl alcohol were added in small increments over aperiod of about 2 hours, and refluxing, at a temperature of about 74-77C., was continued for 6 additional hours. The reaction mixture was thencooled to about room temperature and filtered to remove solid residuestherefrom, and the filtrate was given a water wash. Using -a flashevaporator, the filtrate was stripped of volatiles, mainly carbontetrachloride, at a temperature of 78 C. and a pressure of 15 mm. ofmercury. This was followed by a final stripping at room temperature anda pressure of 0.5 mm. of mercury. The weight of the stripped product, orweight conversion, was found to be 212 grams, and by vapor phasechromatography it was found to be 84.3 percent pure TCBA. Based on this,the conversion of allyl alcohol was calculated to be lOO percent and'theyield (conversion times purity) was determined to be 84.3 percent.

EXAMPLE 2 I COMPARATIVE TEST 1 This test is provided to show that whenthe azobisisobutyronitrile is used asa catalyst in the absence of ironpowder and ferric chloride, the conversion to TCBA is very low.

The identical procedure of Example 1 was followed except that no ironpowder and no ferric chloride were included in the reaction mixture.Based on the initial weight of allyl alcohol charged, the conversion toallyl alcohol in the reaction product was calculated to be only 7.6percent. vThus when no iron-ferric chloride is included in the catalystmixture, along with the azobisisobutyronitrile, inadequate conversion isobtained.

COMPARATIVE TEST 2 The identical procedure of Example 1 was employedexcept that no azobisisobutyronitrile was included in the reactionmixture. The conversion was found to be 90 percent and the yield, 78.4percent. Thus a lower yield is obtained when the azobisisobutyronitrileis exment which comprises employing as said catalyst, a

catalytic proportion of a mixture consisting essentially of about 1-6()percent by weight of iron powder, about 0.5-60 percent by weight of ironchloride, about. l-75 percent by weight of azobisisobutyronitrile, andabout 1-75 percent by weight of calcium carbonate and wherein anantioxidant selected from the group consisting of butylatedhydroxyanisole, butylated hydroxytolu'ene and 2,2-methylene-bis-4-methyl- -tertiarybutylphenol can be optionally presentin amounts of from about 0.5 20 percent by weight based on the totalweight of the catalyst mixture.

2. The process of claim 8 wherein the proportion of said calciumcarbonate in said mixture is about -40 percent by weight. 1

3. The process of claim 1 wherein said catalytic proportion ranges fromabout 0.5 percent to about 25 percent by weight of the total weight ofsaid ally] alcohol and said carbon tetrachloride.

4. The process of claim 3 wherein said iron chloride is anhydrous ferricchloride.

5.. The process of claim 4 wherein said mixture also comprises about0.5-20 percent by weight of said antioxidant.

6. The process of claim 4 wherein said mixture is comprised of about10-40 percent by weight of said iron powder, about 5-40 percent byweight of said ferric chloride, and about l060 percent by weight of saidazobisisobutyronitrile.

7. The process of claim 6 wherein said catalytic proportion ranges fromabout 1 percent to about 10 percent of the total weight of said ally]alcohol and said carbon tetrachloride.

8. The process of claim 7wherein said mixture also

2. The process of claim 8 wherein the proportion of said calciumcarbonate in said mixture is about 10-40 percent by weight.
 3. Theprocess of claim 1 wherein said catalytic proportion ranges from about0.5 percent to about 25 percent by weight of the total weight of saidallyl alcohol and said carbon tetrachloride.
 4. The process of claim 3wherein said iron chloride is anhydrous ferric chloride.
 5. The processof claim 4 wherein said mixture also comprises about 0.5-20 percent byweight of said anti-oxidant.
 6. The process of claim 4 wherein saidmixture is comprised of about 10-40 percent by weight of said ironpowder, about 5-40 percent by weight of said ferric chloride, and about10-60 percent by weight of said azobisisobutyronitrile.
 7. The processof claim 6 wherein said catalytic proportion ranges from about 1 percentto about 10 percent of the total weight of said allyl alcohol and saidcarbon tetrachloride.
 8. The process of claim 7 wherein said mixturEalso comprises about 1-10 percent of said anti-oxidant.
 9. The processof claim 2 wherein said reaction is carried out under reflux and under anitrogen blanket.
 10. The process of claim 9 wherein said anti-oxidantis butyl hydroxyanisole.